1. Field of the Invention
The present invention relates to an X-ray image processing apparatus for processing X-ray images of a subject which have been formed by an X ray diagnosis apparatus.
2. Description of the Related Art
During a medical treatment, a catheter is often inserted into a blood vessel existing in the region of interest of a patient. Seeing the X-ray image of the region of interest, the doctor inserts the catheter, deeper into the blood vessel. The blood vessel is not seen in the X-ray image. To form an image of the vessel, a contrast medium is applied in a small amount from the catheter into the blood vessel, so that the image of the blood vessel appears in the X ray image.
Since the amount of the contrast medium applied into the blood vessel is so small that the image of the blood vessel disappears within a very short time. The data representing the image, which lasts for an extremely short time after the contrast medium has been applied into the blood vessel, is written into a memory. Whenever necessary, this data is read from the memory, and the image of the blood vessel is superposed on the X-ray image of the region of interest.
Usually it is the doctor who applies the contrast medium into the blood vessel, and whereas it is usually the doctor's assistant who pushes or operates the switch for writing the image data into the memory. The assistant must operate the switch the very moment the image of the blood vessel is formed by virtue of the contrast medium, so that the data is written into the memory. It is difficult for the assistant to operate the switch at a desired time. If the assistant operates the switch either too early or too late, no image data can be written into the memory. For the doctor it is impossible to both inject the medium into the vessel and operate the switch, within said extremely short time. Therefore, the doctor cannot help but assign the operation of the switch to the assistant, and as a consequence, the data representing the image of the blood vessel cannot be written into the memory in some cases.